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util.c
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util.c
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/*
* Process Isolator -- Utility Functions
*
* (c) 2012-2017 Martin Mares <[email protected]>
* (c) 2012-2014 Bernard Blackham <[email protected]>
*/
#include "isolate.h"
#include <dirent.h>
#include <errno.h>
#include <ftw.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/fsuid.h>
#include <sys/stat.h>
#include <unistd.h>
void *
xmalloc(size_t size)
{
void *p = malloc(size);
if (!p)
die("Out of memory");
return p;
}
char *
xstrdup(char *str)
{
char *p = strdup(str);
if (!p)
die("Out of memory");
return p;
}
int
dir_exists(char *path)
{
struct stat st;
return (stat(path, &st) >= 0 && S_ISDIR(st.st_mode));
}
void
make_dir(char *path)
{
char *sep = (path[0] == '/' ? path+1 : path);
for (;;)
{
sep = strchr(sep, '/');
if (sep)
*sep = 0;
if (mkdir(path, 0777) < 0 && errno != EEXIST)
die("Cannot create directory %s: %m", path);
if (!sep)
break;
*sep++ = '/';
}
// mkdir() above may have returned EEXIST even if the path was not
// a directory. Ensure that it is.
struct stat st;
if (stat(path, &st) < 0)
die("Cannot stat %s: %m", path);
if (!S_ISDIR(st.st_mode))
die("Cannot create %s: already exists, but not a directory", path);
}
static int
rmtree_helper(const char *fpath, const struct stat *sb, int typeflag UNUSED, struct FTW *ftwbuf UNUSED)
{
if (S_ISDIR(sb->st_mode))
{
if (rmdir(fpath) < 0)
die("Cannot rmdir %s: %m", fpath);
}
else
{
if (unlink(fpath) < 0)
die("Cannot unlink %s: %m", fpath);
}
return 0;
}
void
rmtree(char *path)
{
nftw(path, rmtree_helper, 32, FTW_MOUNT | FTW_PHYS | FTW_DEPTH);
}
static uid_t chown_uid;
static gid_t chown_gid;
static int
chowntree_helper(const char *fpath, const struct stat *sb UNUSED, int typeflag UNUSED, struct FTW *ftwbuf UNUSED)
{
if (lchown(fpath, chown_uid, chown_gid) < 0)
die("Cannot chown %s: %m", fpath);
else
return 0;
}
void
chowntree(char *path, uid_t uid, gid_t gid)
{
chown_uid = uid;
chown_gid = gid;
nftw(path, chowntree_helper, 32, FTW_MOUNT | FTW_PHYS);
}
static int fd_to_keep = -1;
void
close_all_fds(void)
{
/* Close all file descriptors except 0, 1, 2 */
DIR *dir = opendir("/proc/self/fd");
if (!dir)
die("Cannot open /proc/self/fd: %m");
int dir_fd = dirfd(dir);
struct dirent *e;
while (e = readdir(dir))
{
char *end;
long int fd = strtol(e->d_name, &end, 10);
if (*end)
continue;
if (fd >= 0 && fd <= 2 || fd == dir_fd || fd == fd_to_keep)
continue;
close(fd);
}
closedir(dir);
}
/*** Meta-files ***/
static FILE *metafile;
void
meta_open(const char *name)
{
if (!strcmp(name, "-"))
{
metafile = stdout;
return;
}
if (setfsuid(getuid()) < 0)
die("Failed to switch FS UID: %m");
metafile = fopen(name, "w");
if (setfsuid(geteuid()) < 0)
die("Failed to switch FS UID back: %m");
if (!metafile)
die("Failed to open metafile '%s'",name);
fd_to_keep = fileno(metafile);
}
void
meta_close(void)
{
if (metafile && metafile != stdout)
fclose(metafile);
}
void
meta_printf(const char *fmt, ...)
{
if (!metafile)
return;
va_list args;
va_start(args, fmt);
vfprintf(metafile, fmt, args);
va_end(args);
}